Alleviation of Phytophthora infestans Mediated Necrotic Stress in the Transgenic Potato (Solanum tuberosum L.) with Enhanced Ascorbic acid Accumulation

Abstract

Potato is the most widely cultivated non-cereal crop in the world, and like any other crop, it is susceptible to yield losses because of various factors, including pathogen attacks. Among the various diseases of potato, late blight caused by the oomycete Phytophthora infestans is considered as the most devastating disease worldwide. In this study, transgenic potato plants overexpressing the D-galacturonic acid reductase (GalUR) gene with an enhanced level of cellular L-ascorbate (L-AsA) were challenged with Phytophthora infestans to determine the level of stress tolerance induced in those plants. With the onset of pathogen infection, necrotic lesions progressively expanded and became necrotic in the control plants. The transgenic potato lines with enhanced ascorbic acid showed reduced necrotic lesions. Hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels were relatively lower in transgenic plants compared to the untransformed control (UT) plants. The mRNA expressions of pathogenesis-related (PR) genes, such as pathogenesis related 1 (PR1) and phenylalanine ammonia-lyase (PAL) were slightly higher in GalUR overexpressing transgenic lines as compared to the untransformed control plants. Pathogen infection also altered the mRNA expression of genes associated with gibberellic acid (GA) and abscisic acid (ABA) biosynthesis. Furthermore, the increase in various antioxidant enzymes was also observed in the gene expression analysis with the transgenic plants. The complete loss of the pathogen growth and disease occurrence was not observed in our study; however, the findings indicated that an increase in the level of cellular L-ascorbate in the transgenic potato leads to enhanced cellular antioxidants, PR genes and plant defense hormones, such as GA and ABA resulting in the reduction of the disease symptoms caused by the Phytophthora infestans.

Is the Tolerance of Commercial Peach Cultivars to Brown Rot Caused by Monilinia laxa Modulated by its Antioxidant Content?

“…The content of ascorbic acid in peach, until now considered as an important nutritional quality indicator, can be considered more relevant for breeding purposes for its antioxidant role conferring in vivo brown rot tolerance. Our results are consistent with those previously reported in transgenic potato plants with enhanced levels of cellular L-ascorbate that resulted in the reduction of the disease symptoms caused by the oomycete fungi Phytophthora infestans [48]. These transgenic potato plants that overproduced AsA by 1.6-2 folds showed reduced necrotic spots compared to the control leaf and exhibited tolerance to various abiotic stresses due to the enhanced ROS-scavenging activity.…”

Application of a Low-Cost Electronic Nose for Differentiation between Pathogenic Oomycetes Pythium intermedium and Phytophthora plurivora

“…Pythium species are so often abundant in the soil that possibly no action is required while Phytophthora is always considered to cause managers’ problems. Those species usually damage fine roots (less than 2 mm of diameter) and the base of stems (like P. plurivora ) [ 66 ], but also they can attack the upper part of plants ( P. infestans or P. ramorum ) [ 67 , 68 ]. In this case, action is always required, and the earlier, the better, so early detection systems like e-nose cannot be overestimated.…”

Abscisic Acid—Enemy or Savior in the Response of Cereals to Abiotic and Biotic Stresses?

“…As was described in previous sections, ABA is a well-known phytohormonal molecule that is involved in signaling during abiotic stress responses in plants, but the knowledge about its participation in wheat and barley responses against pests and pathogens is still fragmentary. Most research in this area has been conducted on noncereal species, such as Arabidopsis [ 173 , 174 , 175 , 176 , 177 ], Solanaceae species [ 178 , 179 , 180 , 181 , 182 ] or soybean [ 183 , 184 , 185 , 186 , 187 ]. Therefore, the summary of results showing the roles of ABA in wheat and barley responses to biotic factors is important because it can adumbrate future research paths that would be worth following.…”